Title page for ETD etd-05292001-140004

Vegetation Responses to Seven Silvicultural Treatments in the Southern Appalachians One-Year After Harvesting

Degree

Master of Science

Department

Forestry

Advisory Committee

Advisor Name

Title

Zedaker, Shepard M.

Committee Co-Chair

Aust, Wallace Michael

Committee Member

Jones, Robert H.

Committee Member

Smith, David William

Committee Member

Keywords

diversity-stability hypothesis

detrended correspondence analysis

canonical correspondence analysis

shelterwood

plant community

multidimensional scaling

leave-tree

species diversity

Appalachian hardwoods

clearcut

herbicide

group selection

Date of Defense

2001-04-25

Availability

unrestricted

Abstract

The vegetation responses to seven silvicultural treatments one growing season after harvesting were examined on seven sites in the southern Appalachian mountains of Virginia and West Virginia. Treatments included: 1) control, 2) understory control by herbicide, 3) group selection, 4) high-leave shelterwood, 5) low-leave shelterwood, 6) leave tree, and 7) clearcut. The effects of harvesting were compared between treatments and between pre-harvest and post-harvest samplings. Species richness, percent cover, and local species extinctions were calculated for sample plots ranging in size from 1m2 to 2 ha. Vegetation richness and cover increased with increasing harvest intensity. Local species extinctions were similar in the control and disturbed treatments. Additional analyses were performed using the control, high-leave shelterwood, and clearcut on five of the seven sites to determine the relationships between soil, litter, and other environmental characteristics and vegetation in the herbaceous layer (<1 m in height). Multivariate analysis techniques were used to analyze average differences in species abundance between pre-harvest and post-harvest and to relate post-harvest vegetation to microsite characteristics. Regional-scale differences in site location were more important in explaining the presence of a species than were environmental characteristics. Within a region, species primarily were distributed along a light/litter weight gradient and secondarily along a soil properties and nutrient gradient.